The present invention relates to a cap for closing the mouth of a filler neck, and in particular, to a quick-on fuel cap for closing the filler neck of a vehicle fuel tank. More particularly, the present invention relates to a cap including an attachment mechanism for enabling a user to attach the cap to the filler neck quickly and easily and establish a sealed connection between the cap and the filler neck.
Conventional fuel caps for closing the filler neck of a vehicle fuel tank typically include a closure member for closing the mouth of the filler neck and a handle for turning the closure member to mount the closure member in the filler neck. Partial-turn cam-on caps and multiple-turn threaded caps are well-known types of caps for use in closing filler necks. Although such caps are currently in widespread use, it would be desirable to provide an alternative cap that is simpler to install on and remove from a filler neck.
It is known to provide a cam-on cap of the type having a shank portion which extends into the filler neck and is provided with pairs of conventional circumferentially spaced-apart cam lugs as disclosed in U.S. Pat. No. 4,887,733 to Harris. These cam lugs operate in the customary way to engage a filler neck configured to receive a cam-on cap and retain the cap in a fully tightened position closing the open mouth of the filler neck.
Alternatively, a conventional multiple-turn cap includes a closure member that is threaded to be screwed into a threaded filler neck. For example, U.S. Pat. No. 3,820,680 to Friend discloses a multiple-turn threaded cap and a compatible threaded filler neck. Typically, a multiple-turn threaded cap must be turned at least two and one-half or three full revolutions by the user after it is inserted into the threaded filler neck to connect the cap to the filler neck and establish a liquid and vapor seal between the cap and the filler neck.
More and more vehicle drivers are using the self-service bays at gasoline stations and filling their own fuel tanks. Some people have found that it is difficult to remove and install a conventional filler neck cap during refueling. A cap that is readily installable on and removable from a filler neck by a user without a lot of effort and that is configured to establish a sturdy sealed connection between the cap and the filler neck consistently during use would be a welcomed improvement over conventional caps.
It is known to provide a filler neck cap for which it is only necessary for the user to move the handle cover of the cap a small amount relative to the filler neck to tighten or loosen the cap during refueling. See, for example, U.S. Pat. Nos. 5,381,919 and 5,395,004 to Griffin et al. Typically these caps include a partial turn-to-remove feature which allows the user to slide the cap out of the filler neck easily rather than requiring the user to turn the entire cap in the filler neck one or more revolutions.
One problem with many conventional filler neck caps is that, because the handle is directly connected to the filler neck closure, any unintentional movement of the handle in the cap-removal direction will break the seal between the closure and the filler neck. Once the seal between the closure and the filler neck is broken, it is possible for fuel or fuel vapor to escape from the filler neck. In some instances, such as during a vehicle accident, a release of fuel or fuel vapor can potentially create a hazardous condition.
It is known to provide a filler neck cap having a lost-motion driving connection between the handle and the closure. See, for example, U.S. Pat. No. 4,765,505 to Harris and U.S. Pat. No. 5,520,300 to Griffin. These caps are designed to allow the cap handle to rotate freely relative to the closure in both the cap-installation direction and the cap-removal direction.
In some cases, a user might be inconvenienced by a cap that provides a lost-motion driving connection during cap installation as well as during cap removal. It is known to provide a filler neck cap having a lost-motion driving connection between the handle and the closure during cap removal and that is automatically set to have a direct-drive driving connection between the handle and closure during cap installation. See, for example, U.S. Pat. No. 5,480,055 to Harris and Griffin.
Filler neck caps that include a sealing mechanism for establishing a liquid fuel and vapor seal between the filler neck and the sealing mechanism are often configured to ensure that the seal remains intact in the event of trauma such as an impact that might result if the vehicle is involved in a collision. See, for example, U.S. Pat. No. 4,678,097 to Crute disclosing a fuel cap including a flange having a frangible section that allows the handle shell to separate from the closure and sealing ring so that the seal remains intact in the event of such an impact. See also U.S. Pat. No. 5,381,919 to Griffin et al. disclosing a seal ring positioned at an axially inner surface on the closure engaging an axially outwardly-facing sealing surface of the filler neck so that the seal is axially compressed therebetween forming the seal at a position axially within the filler neck.
What is needed is a fuel cap providing a quick-on installation and removal mechanism allowing the user to move the handle a minimum angular distance to tighten or loosen the cap during refueling while providing a lost-motion connection between the handle and the closure that is automatically reset upon removal of the fuel cap from the filler neck to automatically provide a direct-drive driving connection between the handle and the closure during cap installation. In addition, the cap should include a sealing gasket positioned axially inwardly past the mouth of the filler neck when the cap is installed to minimize the disruption of the sealing gasket in the event of a vehicle collision.
The cap should be additionally configured to minimize the wear of the gasket over an extended period of use including repeated installations and removals of the cap from the filler neck. Users will appreciate a cap having a compressible gasket that cooperates with the cap and the filler neck to resist wear of the gasket. Users will also appreciate such a cap that provides a tactile indication of the closure of the filler neck, while both users and vehicle manufacturers will appreciate a dust shield integral with the cap that minimizes the contamination of the fuel in the fuel tank by blocking the ingress of particulate debris into the filler neck.
According to the present invention, a cap is provided that is engageable with a filler neck of a vehicle fuel tank. The cap includes a closure for closing the filler neck and a handle connected to the closure for moving the closure relative to the filler neck. An annular gasket is carried by the closure for sealingly engaging the closure and the filler neck to form a seal therebetween. The seal blocks the escape of liquid fuel and fuel vapor from the filler neck. The gasket includes a radially outer surface engaging the filler neck and a radially inner surface engaging the closure so that the gasket is compressed radially between the closure and the filler neck to sealingly engage both of the filler neck and the closure forming the seal therebetween.
During cap installation, the user always turns the closure in the filler neck in a cap-installation or cap-advancing direction directly by turning the handle about its axis of rotation. The cap is called a "quick-on" cap because a user need only turn the handle one-quarter of a turn (90.degree.) in a clockwise direction once the cap is inserted into the filler neck to anchor the cap in a sealed filler neck-closing position. During cap removal, the user turns the closure in the filler neck in an opposite cap-removal direction.
The closure includes an axially outer upper housing and an axially inner lower housing coupled to the upper housing for rotation with respect thereto. The handle is connected to the upper housing and the sealing gasket is carried by the lower housing so that rotation of the handle does not necessarily result in rotation of the sealing gasket. This allows the sealing gasket to slidingly engage the filler neck as the closure moves axially into the filler neck without rotation of the sealing gasket during cap installation to minimize abrasion of the sealing gasket.
In preferred embodiments, the cap is anchored to the filler neck by retaining means and the retaining means is positioned to lie between the handle and the gasket. This arrangement allows the gasket to be placed axially inwardly a predetermined distance into the filler neck and away from the mouth of the filler neck to minimize the disruption of the seal that might occur in the event of a vehicle collision or undesirable impact to a portion of the vehicle adjacent to the filler neck.
The closure typically includes a cylindrical side wall and the sealing gasket includes an annular hoop-shaped base that sealingly engages the cylindrical side wall of the closure. The gasket also includes an annular outer seal positioned radially outside of the base so that outer portion encircles the base and sealingly engages the filler neck. As the cap is installed into the filler neck, the gasket is radially compressed between the filler neck and the closure to form the seal therebetween to prevent liquid fuel and fuel vapor from escaping the filler neck.
The filler neck in such a closure system includes a cylindrical side wall defining the filler neck mouth and filler neck opening that receives the cap. The cylindrical side wall of the filler neck is formed to include radially inwardly extending helical ramps that cooperate with radially outwardly extending helical ramps formed on the cylindrical side wall of the closure to draw the closure into the filler neck, to draw the sealing gasket into sealing engagement with the filler neck and the closure, to retain the cap in the filler neck, and to retain the sealing gasket in its installed position after installation of the cap.
The cylindrical side wall of the closure includes an axially inner end adjacent to the sealing gasket and an axially outer end coupled to the handle. The helical ramps of the closure are positioned to lie axially between the axially inner and outer ends. Thus, as mentioned above, the sealing gasket is positioned to lie axially inwardly of the retaining means to minimize exposure of the sealing gasket to perturbations that might disrupt the seal formed thereby between the closure and the filler neck.
As the cap is installed into the filler neck, the lower housing slides axially inwardly into the filler neck. The sealing gasket has the hoop-shaped base engaging the cylindrical side wall of the lower housing and additionally has the annular outer seal engaging the filler neck. As can be seen, during the installation of the cap in the filler neck and from the frame of reference of the sealing gasket, as the closure moves axially into the filler neck and the outer seal frictionally engages the filler neck, the hoop-shaped base will be subjected to axially inwardly directed shear forces while the outer seal is subjected to axially outwardly directed shear forces.
With conventional o-ring sealing gaskets these opposing forces would operate to roll the outer seal axially outwardly relative to the hoop-shaped base, much like "rolling" a rubber band along the length of a rolled-up newspaper. The sealing gasket in accordance with the present invention, however, includes a multi-directional connecting membrane connecting the hoop-shaped base to the outer seal that resists these forces. The connecting membrane includes a circumferentially extending inclined first portion that also extends generally axially from the axially inner edge of the hoop-shaped base to the axially outer edge of the outer seal to prevent axially outward rolling movement of the outer seal relative to the hoop-shaped base.
As can be seen, the sealing gasket is also subjected to shear forces during removal of the cap from the filler neck, these removal shear forces acting in the opposite directions of the shear forces encountered during cap installation. During removal of the cap, from the frame of reference of the sealing gasket, the hoop-shaped base is subjected to axially outwardly directed shear forces and the outer seal is subjected to axially inwardly directed shear forces. The multi-directional connecting membrane can also include a circumferentially extending inclined second portion that also extends generally axially from the axially outer edge of the hoop-shaped base to the axially inner edge of the outer seal to prevent axially inward rolling movement of the outer seal relative to the hoop-shaped base.
In preferred embodiments, the connecting membrane includes a plurality of spaced apart inclined first portions sloping in one direction and a plurality of spaced apart inclined second portions sloping in another direction. The inclined first and second portions are arranged in a circumferentially extending alternating pattern to prevent rolling movement of the outer seal relative to the hoop-shaped base during both installation and removal of the cap to and from the filler neck.
Users that are accustomed to conventional fuel caps requiring rotation of the entire cap in the filler neck one or more revolutions may feel uneasy about whether the installation is complete when only one-quarter of a turn or less is required to complete installation. This may particularly be troublesome for the user when the later stage of the installation is spring-assisted so that the torque applied to install the cap remains constant or decreases instead of increasing as installation is completed, as found on many conventional fuel caps.
The closure includes a spring-loaded intermediate housing engaging the upper and lower housings. The intermediate housing cooperates with the upper and lower housings to provide an "over-center" feel to the cap during cap installation. Rotation of the handle in the cap-advancing direction during cap installation operates to move the upper and lower housings axially into the filler neck. In addition, during a first stage of the cap installation, rotation of the handle in the cap-advancing direction loads a power spring of the intermediate housing so that the power spring biases the handle in the cap-removal direction. This causes the torque applied by the user during rotation of the cap in the cap-advancing direction to increase until a maximum torque is reached.
Once the maximum torque is reached, continued rotation of the handle in the cap-advancing direction during a second stage of the cap installation allows the intermediate housing and the power spring suddenly to bias the handle in the cap-advancing direction assisting the rotation of the handle and the installation of the cap. This "crossover" bias provides the over-center feel that provides an indication to the user that the cap is installed properly. In addition, engagement of the intermediate housing with the lower housing at the end of the installation of the cap results in a "snap" providing the user with a tactile and audible indication that installation is complete.
Also in preferred embodiments, the cap is provided with a dust shield for minimizing the ingress of debris into the filler neck to minimize particulate contamination of the fuel in the fuel tank. Advantageously, the dust shield in accordance with the present invention is an annular dust shield integrally appended to the cylindrical side wall of the closure. The dust shield extends radially outwardly from the side wall and slightly axially inwardly before installation of the cap. After installation, the dust shield engages a border around the mouth of the filler neck and is flexed to a position generally perpendicular to the cylindrical side wall to ensure a tight particulate seal is formed between the dust shield and the mouth of the filler neck.
The value of providing a cap for use on a vehicle fuel tank with a tank pressure control mechanism has been generally recognized in the prior art. However, increasingly aggressive government emission standards, such as recent standards requiring vacuum relief at low pressure differentials with increased air flow during vacuum relief conditions have caused some older mechanisms to become obsolete. The cap in accordance with the present invention is provided with a pressure control mechanism meeting such emission standards.
Venting control mechanisms generally include a pressure-relief valve for relieving vehicle fuel tank pressure when the pressure exceeds a predetermined maximum pressure as well as a vacuum-relief valve for relieving the tank pressure when the tank pressure drops below a predetermined minimum pressure. The pressure-relief and vacuum-relief valves each include, respectively, a pressure-relief face that is acted upon by fuel vapor to cause the pressure-relief valve to move to relieve high tank pressure and a vacuum-relief face that is acted upon by negative tank pressure to cause the vacuum-relief valve to move to relieve low tank pressure.
The tank pressure control mechanism according to the present invention includes a vacuum-relief mechanism in which the vacuum-relief face and the pressure-relief valve cooperate to define a larger area upon which atmospheric air can act to cause the pressure-relief valve and the vacuum-relief valve to move to relieve low tank pressure. Increasing the area upon which atmospheric air can act increases the sensitivity of the vacuum-relief mechanism so that the vacuum-relief valve can respond to lower pressure differentials between the vehicle fuel tank and the atmosphere. In addition and as a consequence of both the vacuum-relief and pressure-relief valves moving during the vacuum-relief condition, a larger opening is provided for the flow of atmospheric air allowing for a greater flow rate of air into the fuel tank during vacuum relief.
The quick-on cap can also include control means for initially providing a lost-motion driving connection during cap removal and always providing a direct-drive driving connection during cap installation. The lost-motion driving connection is established temporarily between the handle and the closure during initial rotation of the handle about an axis of rotation relative to the filler neck in a cap-removal direction. The direct-drive driving connection is always established between the handle and the closure during rotation of the handle about the axis of rotation in a cap-installation direction.
Each time the quick-on cap is removed from a filler neck, it instantly and automatically "resets" itself so that a direct-drive driving connection between the handle and the closure is established to facilitate reinstallation of the quick-on cap on the filler neck. This reset function is achieved by automatic operation of a torsion spring provided between the closure and the handle to rotate the closure relative to the handle.
Additional objects, features, and advantages of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of preferred embodiments exemplifying the best mode of carrying out the invention as presently perceived.